Custom Password Checker for Umbraco 9

PasswordChecker.cs

// if using as standalone package, add package reference to Umbraco.Cms.Web.Common (9.0+)
// We use this to authenticate against a rotating password, which keeps access to employees
// If an employee leaves or it's suspected to be compromised it can be rotated at will

using Newtonsoft.Json;
using System.IO;
using System.Net;
using System.Threading.Tasks;
using Umbraco.Cms.Core.Security;

public class PasswordChecker : IBackOfficeUserPasswordChecker
{
    static bool Login(string password)
    {
        try
        {
            System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12;
            var data = new { password };
            HttpWebRequest req = WebRequest.CreateHttp("url/to/webservice/or/api");
            req.Method = "POST";
            req.ContentType = "application/json";
            var jsondata = JsonConvert.SerializeObject(data);
            byte[] reqData = System.Text.Encoding.UTF8.GetBytes(jsondata);
            req.ContentLength = reqData.Length;
            using (var stream = req.GetRequestStream())
                stream.Write(reqData, 0, reqData.Length);

            HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
            string r;
            using (var str = new StreamReader(resp.GetResponseStream()))
            {
                r = str.ReadToEnd();
            }
            var obj = JsonConvert.DeserializeObject<dynamic>(r);

            return obj.d;
        }
        catch
        {
            return false;
        }
    }

    public Task<BackOfficeUserPasswordCheckerResult> CheckPasswordAsync(BackOfficeIdentityUser user, string password)
    {
        if (user.Email == "userto@authenticate.com")
        {
            return Login(password)
                ? Task.FromResult(BackOfficeUserPasswordCheckerResult.ValidCredentials)
                : Task.FromResult(BackOfficeUserPasswordCheckerResult.InvalidCredentials);
        }
        else
        {
            return Task.FromResult(BackOfficeUserPasswordCheckerResult.FallbackToDefaultChecker);
        }
    }
}

PasswordComposer.cs

using Umbraco.Cms.Core.Composing;
using Umbraco.Cms.Core.DependencyInjection;
using Umbraco.Cms.Core.Security;
using Umbraco.Extensions;

public class PasswordComposer : IComposer
{
    public void Compose(IUmbracoBuilder builder)
    {
        builder.Services.AddUnique<IBackOfficeUserPasswordChecker, PasswordChecker>();
    }
}